Industrial and papermaker&#39;s felt



Jan. 8, 1952 P. T. GATES 2;581,790

INDUSTRIAL AND PAPERMAKER'S FELT Filed March 1, 1948 it? a j 1" j; aw,

INVENTOR.

FERELIVAL T EATEE BY a ATTORN EY.

Patented Jan. 8, 1952 ITETD STATES PATENT 'OFI CE INDUSTRIAL PAPER/MAKER'S FELT Percival"'1. Gates, Suflield, 001111., assignor to 'Drycor Felt Company, .Belleville, N. J, a corponation .of New Jersey Application March 1 1948,, Serial No. 123113 is Claims; (01. 23-49) 'The'present invention relates to industrial and paper makers felts, and is directed particularly to an improved woven felt for use in the man- 'nfacture of such paper machine products as puip, =paper, paperboard, asbestos cement products;

millboard, gasket-board, asbestos paper and the like. Such felts are usually in the form of an endless belt, either woven inendless belt form or woven as a fiat fabric which is thereafter joined together at its ends to form an endless belt, the "belt being mounted in the paper making machine upon suitable .rolls. Its principal functions are to impart a finish to the sheet of paper or other material carried on the felt, and {to remove water from it by drainage of the water through the felt, this water removal being accomplished through the cooperation of press rolls, suction boxes, and the like. The paper makers felt thus constitutes a mechanical pare of the paper machine, and in such "use is sub-F il'ected to friction, abrasion, chemical deterioration, and deterioration due to bacterial molds, mildews, f-unguses, etc. Its structural and functional characteristics are therefore peculiarly related to the requirements of its use in paper machines, as distinguished from fabrics designed for other uses such as clothing, carpets, blankets; and the like.

a The invention is concerned with paper makers felts of the woven type, wherein the warp and weft of the weave are comprised principally ofv wool yarns, which are subjected to the process or "fulling for the purpose of shrinking and compacting the fabric and causing the wool fibers to 'felt'with each other. As such felts are usually "made, the fibers of the yarns are required to 'I-Iere'tofore it has been necessary in, order to cushionthe weave, so as to provide a smooth "paper formation surface, that a nap be raised 'on' the" fabric "from the threads or fibers of the woven yarn, such nap fibers being usually raised by brushing or tea-zeling from their more or less horizontal positionin the woven yarn to a more or'less vertical position. The strength of the 7am is-therefore reduced by the "number of fibers which are transposed from their normal position in the spun yarn to raised nap producing position, since in this raised position they cease to contribute to the tensile strength of the yarn. Where it is necessary to raise the nap on the inside surface of the "felt to resist abrasion there is a further substantial loss of tensile strength. Thus in order to give a smooth face surface to the felt or an abrasion resisting back surface, the strength of the warp and weft of the woven felt must to a substantial degree be sacrificed. 'In addition to sacrificing the strength of the felt the mapped surfaces, after a very short period of use, wear down to such an extent that the weave of the felt is exposed on the face surface giving an undesirable weave marking or imprint to the surface of the paper being made, and at the same time there is a progressive wearing down of the knuckles of the woven fabric on the inside surface through the abrasive action of the rolls of the machine upon which the felt-is supported. The useful life of the felt is therefore shortened, requiring frequent stoppage of production to replace the felts.

"The object of the present invention is to provide an improved woven felt in which the nap surfaces are produced by the application through 'needling of pile "fleeces to the woven felt fabric,

the needling process consisting in forcing the fibers of the fleeces into and through the woven felt fabric, thus leaving parts of the fibers upon the surface to form a cushioning paper formation or abrasion resisting surface, while other portions of the fibers are engaged in the woven fabric and interlocked with the fibers thereof as well as with other fibers of the added fleeces. The needl ing of the fleeces to the woven felt fabric is preferably carried out by the needl'ing method as disclosed for instance in the Reissue Patent No. 21,890, reissued August 26, 1941, to

Patrick H. Walsh and Percival "1. Gates for Ir-idustrial and Paperrnakers Felts. I

It is proposed according to the invention to add pile fleeces by needling to the woven felt fabric, such pile fleeces consisting of any desired fibrous material best suited to carrying out "the functions-and purposes of the paper makers felt. For instance, the added pile fleeces may consist entirely of one kind of fibrous material, such as wool or other natural fibers, or of syn thetic fibers, or it may consist of blends in any desired percentages of natural and synthetic fibers. Also the material applied to the face may be different from that applied to the-inside surface of the felt, so that material having the best paper surface formation characteristics may be applied to the face and material having the of paper making felts to continue to full while in use on the paper machine. This continued fulling causes the felts to become progressively more dense and in so doing tends to rapidly fill up with dirt and other foreign material. It is also possible to employ synthetic material in the added fleeces, which, in addition to bein highly resistant to friction and abrasion, is also highly resistant to chemical deterioration and deterioration due to bacterial molds, mildews, funguses, etc. Synthetic material may be employed which has a smooth and slippery surface so that dirt and other foreign substances passing through the felt with the drainage water do not adhere to the fibers, as they do in the case of wool, which has a scaly surface and makes the felt susceptible to filling up after a relatively short use in the paper machine.-

Thus, by increasing the percentage of fibrous material having these characteristics these advantages are proportionately increased.

A suitable synthetic fiber material having the desired characteristics for obtaining the advantages made possible by the invention is the polyamide known as nylon. Other suitable matefabric by napping. Furthermore, the needled-in fleece surface is more compact than the usual napped' surface of the heretofore known type of woven felt and is, therefore, more resistant to wear. In particular, the application of the added fleeces to the inside surface or wear side of the felt, has the important advantage of protecting the knuckles of the woven felt to such a great extent that the useful life of the felt is materially increased. For instance, where resistance to abrasion of a very high order is desired, it is possible to produce a wearing surface for the woven felt consisting wholly of synthetic fiber such as nylon which is far more resistant to abrasion than wool or a blend of wool and nylon.

With the above and other objects in view, an embodiment of the invention is shown in the accompanying drawing, and this embodiment will be hereinafter more fully described with reference thereto and the inventionwillbe finally pointed out in the claims. v

' In the drawings:

Fig. 1 is a plan view of a paper makers felt in the form of an endless belt, according to the invention, a portion of the woven felt fabric being shown without pile fleece fibers attached line 2-2 of Fig. 1.

Fig. 3 is an enlarged transverse sectional view showing a portion of the felt.

Referring to the drawings, thepaper makers felt, according to the illustrated exemplary embodiment of the invention, is in the form of an endless belt comprising a woven felt base consisting of warp yarns l0 and weft yarns I I, preferably consisting of wool fibers. This fabric is subjected to the usual treatment of fulling," whereby it is shrunk and compacted and the woolen fibers are caused to felt together. These operations are well known in the art, and a detail description thereof is therefore not necessary. The woven felt fabric is not subjected to the usual brushing or teazeling operation in order to raise a nap on its surfaces, but the surfaces are left substantially intact, so that the felted wool fibers will remain as nearly as possible in their original substantially horizontal position in the yarns in order to maintain their maximum tensile strength.

At at least one side, and preferably at both sides, pile fleeces l2, of suitable fibrous material are needled into the woven felt fabric after it is fulled in order to .provide a cushioning layer at one or both sides, this layer when applied to the face providing a paper formation surface and when applied to the inside surface providingan abrasion resistance surface forengagement over the rolls supporting the felt and over the press rolls, suction boxes, and the like over which the felt passes.

The needling process consists in applying one or more bats, layers, or pile fleeces of fibrous material to the surface of the woven felt fabric and progressively needling it into and through the fabric, the material being graduallymoved beneath vertically reciprocating needles which force the fibers into and through the fabric. In practice one or more layers or fleeces are needled at each side of the felt fabric, and aftersuch layers are attached they may be subjected to a further needling operation without the addition of fibrous material, so as to cause a tuck-in and further interlocking of the fibers at each side of the felt.

According to the invention the fiber material may consist wholly of natural fibers, such as wool, or wholly of synthetic fibers, such as nylon, or it may consist of a blend of natural and synthetic fibers in any desired percentages. The face surface may, if desired, have different material needled thereto than the material needled to the inside surface. Because of the fact that the needled fibers are attached to the woven felt fabric by forcing portions of the fibers vertically into and through the fabric so asto interlock,

therewith and with other ofthe needled fibers, and does not depend forattachment upon fulling? and felting of the fibers, it is possible to employ in the needled layers non-fulling synthetic fibrous material, such as nylon, having advantageous properties that are notppresent, for instance, in wool fibers.

Among these properties are the following}: relatively great tensile strength permitting long fibers to be needled back and forth through'the material without breaking; smoothness of the fibers which provides for better drainage; resistance to-fulling when the felt is in use on the paper machine, eliminating or greatly reducing the tendency of the felt to become progressively more dense and in so doing to fill up with dirt and foreign material; increased resistance to abrasion; and increased resistance to deterioration from chemical action and from .the effects of bacterial molds, mildews, funguses, etc. The invention furthermore permits of the relatively inexpensive reconditioning of usedfelts through the addition of pile fleeces thereto by needling before any abrasive wear takes place upon the knuckles of the woven felt fabric.

What is claimed is: 1. A paper makers felt for supporting and draining paper making material, comprising a woven felt base and a non-woven nap cushion at one side of said base interlockingly needled thereto, said base consisting of warp and weft yarns of fullable fiber material felted together by fulling preliminarily to the needling of said nap cushion thereto to provide a felted fibrous body for interlockingly receiving the needle directed fibers of said nap cushion, said nap cushion consisting of a fleece of unwoven fibrous material, the individual fibers of which are disposed partially at said one side of said felt base in the form of a nap cushion and partially through said felted base in a direction perpendicular thereto to direct drainage through said felted fibers of the base in a direction following the direction of said needled fibers.

' 2. The invention as defined in claim 1, further characterized in that said fleece of fiber material is composed at least in part of non-fullable fibers.

3. A paper makers felt for supporting and draining paper making material, comprising a woven felt base and non-woven nap cushions at the opposed sides of said base interlockingly needled thereto, said base consisting of warp and weft yarns of fullable fiber material felted together by fulling preliminarily to the needling of said nap cushions thereto to provide a felted fibrous body for interlockingly receiving the needle directed fibers of said nap cushions, said nap cushions each consisting of a fleece of unwoven fibrous material, the individual fibers of which are disposed partially at said respective sides of said felt base in the form of a nap cushion and partially through said felted base in a direction perpendicular thereto to direct drainage through said felted fibers of the base in a direction following the direction of said needled fibers.

4. The invention as defined in claim 3, further characterized in that at least one of said fleeces f fiber material is composed at least in part of non-fullable fibers.

5. The process of making paper makers felt for supporting and draining paper making material, which consists in interlockingly needling a non-woven nap cushion consisting of a fleece of unwoven fibrous material at one side of a woven felt base consisting of warp and weft yarns of fullable fiber material felted together by fulling preliminarily to the needling of said nap cushion thereto to provide a felted fibrous body for interlockingly receiving the needle directed fibers of said nap cushion, the needling operation disposing the individual fibers of said fieece partially at said one side of said felt base in the form of a nap cushion and partially through said felted base in a direction perpendicular thereto to direct drainage through said felted fibers of the base in a direction following the direction of said needled fibers.

6. The process of making paper makers felt for supporting and draining paper making material, which consists in interlockingly needling non-woven nap cushions consisting of fleeces of unwoven fibrous material at the respective opposed sides of a woven felt base consisting of warp and weft yarns of fullable fiber material felted together by fulling preliminarily to the needling of said nap cushions thereto to provide a felted fibrous body for interlockingly receiving the needle directed fibers of said nap cushions, the needling operation disposing the individual fibers of said fleeces partially at said sides of said felt base in the form of nap cushions and partially through said felted base in a direction perpendicular thereto to direct drainage through said felted fibers of the base in a direction following the direction of said needled fibers.

PERCIVAL T. GATES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS v Date 

